In Windows, when your system hangs, you can always press Ctrl-Alt-Delete, wait for the Task Manager to open, and kill the process that doesn’t respond. However, Ctrl-Alt-Delete don’t always work the way you want it to leaving you no other option but to do a hard-reset, and perhaps as a result corrupt your data kissing your important files goodbye.

In Linux, when your entire system freezes, there are plenty of safe ways to exit and get back on track immediately. Alt + SysRq + (a selection of other keys) will do the magic trick. Note: 'SysRq' key is equivalent to the 'Print Screen' key.

Alt + SysR + KKill all processes (including X), which are running on the currently active virtual console.

Alt + SysRq + ESend the TERM signal to all running processes except init, asking them to exit.

Alt + SysRq + URemount all mounted filesystems as read-only. This has the same effect as the sync combination above, but with one important benefit: if the operation is successful, fsck won't have to check all filesystems after a computer hardware reset.

Alt + SysRq + RTurn off keyboard raw mode. This can be useful when your X session hangs. After issueing this command you may be able to use .

Alt + SysRq + BReboot immediately without syncing or unmounting your disks. Using this, you will likely end up with filesystem errors, so this is not highly recommended.

Alt + SysRq + OShut the system off right away.

If all these ‘Alt + SysRq’ keyboard combo are hard to remember, you can press Alt + SysRq + H to display a helpful list of the shortcuts above.